1. Field of the Invention
This invention relates to mining implements in general and more particular to the scaling or flaking operation involved with the removal of loose materials from the roof and ribs of salt mine caverns and passages.
2. General Background
Mine scaling is a safety-related job generally practiced in all underground mining operations. When an ore body is removed the passages and caverns remaining have a natural tendency to "close in" as a result of the surrounding geologic pressure. Mining operators go to great lengths to shore-up the roofs and walls of the passages to prevent "cave-ins." Since it is impractical to totally encase such caverns and passages, the geologic pressure exerted between the supports causes a spalling phenomena which results in loose material clinging to the mine's roof and walls (ribs). This loose material called flakes or scales falls at unpredictable times, thus being a hazard to men and equipment and often causing serious injury or severe damage to equipment. This problem is most acute in salt mines as a result of the very large caverns and reduced anchoring and shoring capability.
To prevent accidents from falling debris mine personnel routinely remove loose materials from the mine's roof and walls (ribs) through an operation called "scaling." In some cases scaling involves putting laborers on platform lifts whereby pry bars and pneumatic hammers are used to chip and gouge in any suspicious cracks or spalled areas. In more resent instances sophisticated mechanized equipment utilizing extendable boom cranes with hydraulically operated "fingers" or pneumatic hammers have been used. Others have employed boom vehicles with rotating chains to simply beat the loose material from the roof.
The equipment and methods discussed above are labor intensive, expensive or require dedicated equipment which is often expensive to maintain or impractical to use in the harsh environment of mines.